8 ÷ (7 - 9) * ( 4 + (-4) ) <--- notice that bolded part.
4 + (-4) = 4 - 4 = 0.
after that, you're pretty much dividing and multiplying by 0, so
whatever ÷ whatever * whatever * 0 = 0.
Answer:
N = 3/8
Step-by-step explanation:
let the number be N
let's express the word sentence as a mathematical expression:
"a number multiplied by 2/5"
= "N" multiplied by 2/5
= N x (2/5)
= (2N/5) ------- (1)
"a number multiplied by 2/5 is 3/20" can be written as:
(2N/5) = 3/20 (multiplying both sides by 5)
2N = (3/20) x 5
2N = 3/4 (divide both sides by 2)
N = (3/4) ÷ 2
N = (3/4) x (1/2)
N = 3/8
so... notice the example there, with 8
so.. you tell us, what is the relationship then?
The equation to model this would be 65 = 11r + 9s.
In this equation, we know that the total number he works is 65. We also know he burns 11 every time he runs for an hour. Therefore we can multiply 11 by r. We also know he burns 9 for every hour he spends swimming. Therefore we can multiply 9 by s.
When we put all three of these things together, we get 65 = 11r + 9s.
